The letter — which had appeared nowhere else — helped reinforce TheSkeptic’s image as someone close to Herbalife, if not an insider then certainly a savvy Wall Street type or even a shareholder.

The February tweet was one of nearly 1,800 by TheSkeptic over 15 months — an average of four per day, seven days a week — that cemented an insidery image that led investors and others following the Wall Street battle over the multi-level marketer of nutritional shakes to take the information seriously.

Last year, TheSkeptic tweeted several times that the Federal Trade Commission was not probing Herbalife. The tweeter also told his followers that a respected analyst for Bill Ackman’s Pershing Square hedge fund — which bet $1 billion Herbalife was a fraud, thrusting the small Los Angeles company into the bright lights of the national business media — had been fired.

While the accuracy of some of the tweets was questionable, they definitely grabbed people’s attention.

“It was obvious TheSkeptic was in places others weren’t,” one Herbalife investor, who exchanged private messages with the anonymous tweeter through Twitter, told The Post recently.

Who was this unidentified tweeter and blogger, many wondered, and how was TheSkeptic getting these “scoops” about the company — some of which appear to have helped goose Herbalife shares?

As it turns out, the anonymous blogger is neither an insider nor a finance pro but Jeffrey Gardner, 37, a cancer researcher at New York City’s Memorial Sloan-Kettering, an investigation by The Post and research by Pershing Square, shared with The Post, has shown.

Gardner’s obsession with Herbalife — he also created a Skeptic blog, sent requests to regulators asking whether Herbalife or Ackman were under investigation, and listened to Herbalife earnings calls that usually attract just Wall Street analysts — is the latest strange twist in the saga of this company.

The fight over Herbalife has become a blood sport since Ackman announced his supersized bet. Fellow billionaire Carl Icahn took the other side of the wager, with their animosity toward each other spilling into public view in a riveting and impromptu live debate on CNBC. More than a dozen hedge funds also piled into the stock.

Ackman has spent millions of dollars to convince local and federal lawmakers to push regulators to investigate the company. Herbalife has also doled out cash for lobbying efforts and legal fees to stop any potential probe from happening — unsuccessfully, as it turns out.

On March 12, the FTC announced it was investigating Herbalife, and probes by several other agencies and state attorneys general have also come to light.

While it is clearer why Ackman (huge profits and an ego boost) and Herbalife (a fight for its survival) are battling, why would Gardner devote so much time and effort to boost Herbalife and keep his identity secret?

To hear them tell of their life together, it was a perfect combination of yin and yang, a heady mixture of science and finance. The two painted a picture of a young Manhattan power couple, even creating a website documenting their union, with the title “This is our story.”

There is no evidence Chin wrote any of the blog entries or tweets. But certain facts raise questions about the extent of her involvement in TheSkeptic’s activities.

For example, last Oct. 10, a blog post by TheSkeptic tried to calculate the size of Herbalife’s public share float. Less than three weeks later, Chin, on an earnings conference call, asked Herbalife brass about the same thing.

During much of 2013, as Gardner was writing hundreds of pro-Herbalife tweets, Visium, a $6.5 billion fund founded by Dr. Jacob Gottlieb, was building its Herbalife stake, regulatory filings show.

In the last six months of 2013, Visium’s Herbalife holdings grew by 35 percent, filings show, and the value of those holdings more than doubled, to $30.9 million, as the stock price increased.

Meanwhile, over this same time period, Chin was a prominent and visible Herbalife supporter. She was the only hedge fund analyst to ask questions on the company’s quarterly conference calls since its battle with Ackman began, a review of the transcripts shows.

Herbalife CEO Michael Johnson

“We have a strong history … You know us very well,” Herbalife CEO Michael Johnson said on the company’s July 30 call, in response to a question from Chin.

There is good reason for Chin not to tweet or blog about Herbalife. Most hedge funds, including Visium, forbid employees from sharing information about the stocks they cover, not to mention tweeting about them, anonymously or otherwise, industry sources said.

Chin did not return requests for comment.

The inside scoop

While’s Chin’s position regarding Herbalife remained among the most bullish on Wall Street, Gardner was going to great lengths to keep TheSkeptic anonymous.

Gardner used an IP address near Sloan-Kettering to publish some of the tweets and blog posts, according to research by Pershing Square, which also showed that he made calls from a pay phone. Other sources said he used a hard-to-track Google phone number to call them.

Gardner started his “TheSkeptic21” Twitter avatar on Feb. 7, 2013, just days after the much-viewed on-air CNBC battle between Icahn — who would eventually take a 17 percent stake in the company — and Ackman.

Over the thousand-plus tweets, most of them boosting Herbalife — and the position advocated by his girlfriend — Gardner has also attacked those he believed were anti-Herbalife, including Ackman and even this reporter.

Sometimes the attacks were impressive scoops.

Like the time Gardner tweeted that Ackman was about to post a scathing takedown of John Tartol, an Herbalife board member and veteran distributor.

Gardner was so on top of his game that the tweet of Ackman’s upcoming Tartol takedown beat an exclusive story in the LA Times on the subject by almost two hours.

“How does Ackman respond to ‪$HLF’s killer earnings… and strong guidance? He’s going to release a John Tartol smear today,” Gardner wrote on TheSkeptic’s twitter feed.

Pershing Square was perplexed to see the news break on TheSkeptic’s Twitter feed because, it said, it did not tell anyone but the LA Times reporter about the event.

What is clear from the LA Times story is that its reporter reached out to the company for comment before publishing the story. That put the Tartol story info, in all likelihood, in the hands of just three parties — Ackman, the LA Times reporter and Herbalife.

So how did TheSkeptic know?

Herbalife declined to specifically address the Tartol scoop — as well as the earlier “Friends of Herbalife” letter.

Dinneen had conducted some of Pershing’s original Herbalife research and had been on stage with Ackman on Dec. 20, 2012, during the activist’s three-hour presentation that drove Herbalife stock down 10 percent that day.

The Dinneen tweets led market participants to believe Ackman was backing down on his Herbalife bet, which was deeply in the red at that point. The Dinneen tweets helped send Herbalife stock, nearing its peak of the year, up 2 percent to $79.58 that day.

But Dinneen had not been fired, and Pershing Square demanded that TheSkeptic retract the “fired” comment, which he did. Dinneen left Pershing Square earlier this year for personal reasons and remains an investor in the hedge fund.

More recently, Gardner, as TheSkeptic, hinted that Ackman may have received a Wells notice, which the Securities and Exchange Commission delivers when it is about to take an enforcement action.

“Is this ‪#ackman’s way of disclosing a Wells?” TheSkeptic asked on March 27 in reference to a Wall Street Journal report that the SEC had subpoenaed 25 hedge funds about their trading in Herbalife.

Pershing Square told The Post that neither Ackman, the firm nor any of its employees has received a Wells notice.

Winding down

As the Ackman-Herbalife battle rolls past its 17-month milepost, life for Gardner and Chin is changing.

While Gardner may have seen his Skeptic character as a superhero type coming to the aid of the woman he loves, Chin no longer works at Visium.

She left sometime in March, according to the hedge fund, which sold down its Herbalife position from about $30 million to a little over $1 million as of March 31, filings show.

Visium also has sold its entire stakes in two other companies — NuSkin and Ariad Pharmaceuticals — that TheSkeptic blogged about.

The circumstances of Chin’s departure are not known.

Gardner, as TheSkeptic, is slowing down. After averaging four tweets a day for 15 months, Gardner has tweeted just five times in the last three weeks.

And while Herbalife shares, which closed Thursday at $63.20, are still above the level just prior to Ackman’s much-ballyhooed short, they are off 20 percent this year.